nixos/glance: fix broken server stats (#395859)

        ProtectKernelModules = true;

        ProtectKernelTunables = true;

        ProtectControlGroups = true;

        ProcSubset = "pid";

        ProcSubset = "all";

        RestrictNamespaces = true;

        RestrictRealtime = true;

        SystemCallArchitectures = "native";